It has been known that implantable defibrillation leads, especially transvenous leads, typically employ elongated coils as electrodes. These electrode coils are coupled at one or both ends to an elongated conductor extending through the lead body to the electrode. Transvenous pacing leads, cardiac ablation catheters and other electrode bearing leads and catheters may also employ coil electrodes. Over the years, quite a large number of different mechanisms for interconnecting coil electrodes and conductors have been proposed including welding, crimping, and swaging. It is desirable that such connections between the conductor and the electrode provide a highly reliable electrical connection, with good mechanical properties including high tensile strength. It is also desirable that such connections allow for the lead assembly itself to retain a high degree of tensile strength through the area of the electrode.
Typically, conductors in commercially marketed pacing and defibrillation leads have taken the form of single or multifilar wire coils. However, there has been a high level of recent interest in pacing and defibrillation leads employing stranded wire conductors such as cables, instead of coiled wire conductors. Such stranded conductors present a new set of requirements for interconnection with electrode coils, if the above described design goals are to be accomplished. The present invention relates to this more recent lead technology.
Typical of the prior art in this regard is U.S. Pat. No. 5,591,142 to Van Erp which discloses encasing wires within a metal sleeve and U.S. Pat. No. 5,676,694 to Boser et al. which discloses laser welding an electrode to a sleeve and covering the electrode with a polymeric sleeve.
Other patents, as follows, disclose positioning wires outside of a conductor with subsequent mounting thereon of an electrode or the like:
Pat. No. Inventor(s) Issued 5,632,274 Quedens et al. 05/27/97 5,499,981 Kordis 03/19/96 5,409,652 Carter 04/25/95 5,251,643 Osypka 10/12/93 4,777,955 Brayton et al. 10/18/88 4,522,212 Gelinas et al. 06/11/85
it was with knowledge of the foregoing state of the technology that the present invention has been conceived and is now reduced to practice.